Stabilized pyrethrum



Patented Nov. 3, 1942 UNITED STATES PATENT OFFICE STABILIZED PYRETHBUMNo Drawing. Application September is, 1939, Serial No. 295,210

This application is a continuation in part of our co pending application'Serial No; 643,290, filed sect life and which retain their desirableinsecticidal properties over a relatively long period of time.

Pyrethrum, which contains the active insecticidal principles, pyrethrinsI and II, commercially may be had in two forms as a powder which isproduced by pulverization of pyrethrum flowers, and as an extractobtained by solvent extraction of pyrethrum flowers.

Pyrethrum, which possesses excellent insecticidal properties, onexposure to light and air or oxygen, gradually loses its desirableproperties and in the course of time becomes inefiective and useless. v

This invention involves the discovery that this gradual deterioration ofpyrethrum can be materially retarded by incorporation therewith ofcertain substances which prolong its eflective life and which does notmaterially interfere with the action thereofas an insecticidalcomposition.

We have discovered that certain compounds embraced in the class ofaromatic amines can be employed as such stabilizers of pyrethrum. Wheresuch stabilizer amines are relatively volatile in character, exposure ofthem over relatively extensive surfaces, such as occurs when aninsecticide is spread, as by spraying, upon vegetation or other commonmaterials on which insecticides are applied, would result in a gradualloss of the stabilizer amine through vaporization.

Reduction of volatility of aromatic amines so as to obtain permanencewith pyrethrum or similar insecticides, is obtained by the introductioninto. the hydrocarbon nucleus of the aromatic amine certain substituentssuch as chlorine, hydroxy, carboxyl, or similar groups.

The present invention relates to a composition of matter containingpyrethrum, together with 9 Claims. (Cl. 167-24) 'our discovery mula:

NHX

do 0 Y wherein R is an unsubstituted or substituted aryl radical, X is amember of the group consisting of hydrogen, and alkyl, acyl, aryl'andaralkyl radicals and Y is a member of the group consisting of hydrogen,and ester-forming radicals, such as those derived from monoorpoly-hydroxy a1- cohols. Examples of such radicals are butyl, amyl,octyl, benzyl, butylene, amylene, octylene and the like, as well as thehydrocarbon residues of the glycerols or other polyhydric alcohols.While the present invention, from its broader aspect, is not to belimited to oil soluble esters of the above compounds, it is desirablethat the esters be oil soluble since "it will facilitate incorporationof them into the oil which is to serve as the vehicle for the pyrethrum.Such oil vehicle may be petroleum hydrocarbons. A specific example of acompound of the above general formula is anthranilic acid which embodiesa benzene nucleus and in addition a carboxyl group which serves toreduce the volatility of the simple amine. Chlorine atoms may beintroduced into the benzene nucleus of this coinpound and specificexamples of such chlorine substituted anthranilic acids are themono-chlorand di-chlor compounds. It will be understood that the hydroxysubstituted anthranilic acids are also embraced within the scope of theinvention. It will befurther understood that the polynuclear aromaticamines as well as the mononuclear aromatic amines may have furthersubstituent groups in the hydrocarbon nuclei in addition to the carboxylgroup present.

Typical of the. anthranilic acid compounds which may be used asstabilizers of pyrethrum are the following: anthranilic acid, acetylanthranilic acid, methyl anthranilic acid, benzyl anthranilic acid,mono-nuclear aryl substituted anthranilic acids, such as phenylanthranilic acid, dinitro phenyl anthranilic acid, o-tolyl anthranilicacid, p-tolyl anthranilic acid, m-xylyl anthranilicacid, toluol-sulfoanthranilic acid and di-nuclear aryl substituted anthranilic acids, suchas beta-naphthyl anthranilic acid and naphthalene-sulfo anthranilicacid. Typical of polynuclear aromatic amines which may be employed, isamino naphthoic acid and substitution products thereof analogous to thesubstituted anthranilic acids.

The compositions containing pyrethrum and a stabilizer for theinsecticide are not to be limited to the inclusion therein of thestabilizers in their I uncombined form, 1. e., where the carboxyl groupof the aromatic amine is in its free or unsubstihave the following 8 ffj tuted form, but the aromatic amines may be present in the compositionas stabilizers in the form of oil-soluble salts or esters. Suchoil-soluble salts may be formed by reaction between the carboxyl groupof the aromatic amine and an organic base, for example, diphenylguanidine, amyl amine and the like. Oil soluble esters may be formed byesterifying the carboxyl group of the aromatic amine with alcohols whichgive esters which are soluble in oils such as petroleum hydrocarbons,for example, with butyl, amyl, octyl, benzyl, and the like alcohols.

' The stabilizing material may be incorporated with pyrethrum insubstantially any desired or convenient manner; for example, thepyrethrum consisting of hydrogen, and ester-forming radicals which formoil-soluble esters.

3. A composition of matter containing pyrethrum and in addition anoil-soluble ester formed by the reaction between an organic base and thecarboxyl group of a compound of the formula NHX ' wherein R is an arylradical X is a member may be dissolved in a solvent such as acetone 7which is also a solvent for most of the stabilizers, and then thestabilizer may be incorporated therewith. The choice of solvents will begoverned by the solubility therein of both the insecticide' and thestabilizer. The amount of stabilizer amine to beadded to the insecticidemay vary between 10 to 100% of the weight of the insecticide dependingupon the eflectiveness of the stabilizer and/or the extent to whichstabllization is desired. Oi course, amounts of stabilizer of less than10% may be employed where a particular stabilizer is especially effectve.

It will also be understood that any two or more of the above describedstabilizers may be mixed and the mixture employed with pyrethrum.

- These mixtures may under some circumstances of the group consisting ofalkyl, acyl, aryl, and aralkyl radicals.

4. A composition of matter containing pyrethrum and in addition acompound of the formula be more desirable than any of the compounds 5used singly. It will, also be understood that stabilizers, such as abovedescribed, may be incorporated with pyrethrum powder, with or withoutinert diluents such as kieselguhr or the like, which are used fordusting purposes.

The above compounds employed as stabilizers do not decompose thepyrethrum or appreciably retard the activity thereof as an insecticide,but instead, in some cases, the stabilizers themselves may exhibitconsiderable insecticidal power and thus increase rather than decreasethe insecticidal activity of the mixture.

Although we have set forth above only certain compounds as stabilizersof pyrethrum, these compounds are to be taken as indicative of theextent of our discovery, rather than as limiting the scope of theinvention, which is set forth in the appended claims.

We claim:

1. A composition of matter containing pyrethrum together with a compoundof the formula NHX COOY wherein R is an aryl radical, X is a member ofthe group consisting of alkyl, acyl, aryl, and aralkyl radicals and Y isa member of the group NHX COOH wlierein R is a mono-nuclear. arylradical and X is a mono-nuclear aryl radical.

5. A composition of matter containing py-' rethrum and in addition acompound of the formula NHX coon wherein R is a mono-nuclear arylradical and X is an alkylated benzene radical.

6. A composition of matter containing pyrethrum and in addition acompound of the formula NHX

coon wherein R is a mono-nuclear aryl radical and X is a methylatedbenzene radical.

7. A composition of matter containing pyrethrum and in addition acompound of the formula c o'on wherein R is a mono-nuclear aryl radicaland X is a tolyl radical.

8. A composition of matter containing pyrethrum and in addition acompound of the formula COOH wherein R is a mono-nuclear aryl radicaland X is a di-nuclear aryl radical.

9. A composition of matter containing py-., rethrum and in addition acompound of the formula COOH ,wherein R is a mono-nuclear aryl radicaland X is a beta naphthyl radical.

LUDWIG J. CHRIS'I'MANN. DAVID W. JAYNE, JR.

